Model 200SB


  • Lightweight, compact portable tritium air monitor
  • Extremely fast response: 5 seconds to reach 90% of final value
  • Rapid warm-up of less than 30 seconds
  • Coaxial gamma compensation (200cc volume)
  • Medium sensitivity: 10 µCi/m3, 1 MPCa, or 0.4 MBq/m3
  • Wide range: 10 to 199,990 µCi/m3, 0.1 to 1,999.9 MBq/m3, or 1 to 19,999 DAC/MPCa
  • Audible and visual alarm indicators for low flow, low battery, and signal level
  • Alpha pulse suppression, radon rejection
  • No long-term drift, no manual zero adjustments
  • Offset potentiometer control included
  • CE Marked


The Model 200SB is a low-cost, lightweight, portable tritium in air monitor.  A rapid warmup, high-volume rotary vane pump, and fast electronics combine to give this tritium monitor a very quick overall response time of just 5 seconds or less.  The Model 200SB uses two coaxial 200cc ionization chambers, one for measurement and one for gamma compensation.  The 200SB is our economy model, with medium sensitivity, a wide range, and very fast response.  Particularly useful as an emergency tritium monitor due to compact size and rapid warmup and response.

Power is supplied by a pair of “D” size alkaline batteries.  Onset of the battery depletion is signaled by illumination of an LED located next to the meter face.  A nine-position alarm level stepped attenuator, adjustable over partial scale (.01 – 5%) is located on the front panel.  A steady tone is emitted by an acoustic signaler if the measurement exceeds the alarm set-point (illuminates red LED), or if the sample airflow has been interrupted and is too low (illuminates yellow LED).  The alarms are non-latching.

Zero adjustment is unnecessary, the electrometer is completely temperature stable and shows zero drift from 0° C to 50° C due to special design and careful selection of an ultra-high impedance semiconductor with low internal current leakage and long-term DC stability.  The 200SB can reliably measure currents as low as 10-16 amperes and the span calibration is permanently stable.  The ionization chamber polarizing voltage is supplied by an electronic low-noise regulated dual high-voltage power supply (±80VDC).  The 200SB includes proprietary radon recognition and elimination circuitry to provide accurate, fast, and drift-free measurement.

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